Anionic surfactant, particularly, alkyl sulfate and alkyl polyoxyalkylene sulfate, is excellent in detergency and foaming power, and thus are widely used as cleansing ingredients for domestic or industrial use. An olefin sulfonate, particularly, an internal olefin sulfonate obtained with an internal olefin having a double bond inside an olefin chain, not at its end, as a raw material, has been reported as one of the anionic surfactant.
Such an internal olefin sulfonate is generally obtained by sulfonating an internal olefin through reactions with a gaseous sulfur trioxide-containing gas, followed by neutralization and then hydrolysis of the resulting sulfonic acid. For example, Patent Document 1 discloses an improved production method thereof.
The internal olefin sulfonate thus obtained is known to have good biodegradability or the like, but is still insufficient in a basic performance as cleansing agent including foamability and foaming speed, compared with general-purpose surfactant such as alkyl polyoxyalkylene sulfuric acid ester salt. Thus, further improvement in such basic performance has been desired. As more people have concerned the water-saving or consumers' preferences have been diversified in recent years, the additional value of foam dissipation property free from a slimy feeling and a good feel after drying in addition to good foamability has also been required for use as major activator in laundry detergents, dishwashing detergents, shampoos or the like. Specifically, it has been desired to develop a surfactant composition having excellent foam dissipation property free from a slimy feeling during rinsing while bringing about a good feel without perceivable residue from the cleansing agent after cleansing and subsequent drying. Such an additional value is useful for, for example, body cleansers and hair shampoos. As more people have a habit to wash their hair or bodies within a limited time before leaving the house after awakening, or before going to bed, they are unsatisfied with a long time required for rinsing or an unpleasant feel after cleansing and subsequent drying. Particularly, young people, who have active metabolism and secrete a large amount of sebum, etc., tend to strongly desire a refreshed feel free from a slimy feeling on their scalps or bodies. If a surfactant composition which exerts foam dissipation property free from a slimy feeling and a good feel after drying can be formulated, this composition not only permits rinsing in a short time but can bring about a refreshed feel after drying, leading to the realization of water-saving.
Then, Patent Document 2 discloses a specific internal olefin sulfonic acid which is intended to impart the solubilizing ability, penetrating ability, and interfacial tension reducing ability as a cleansing component. It discloses that when it is used as, for example, a shampoo, it lathers well without friction, and achieves an improved feel. Patent Document 3 also describes a specific internal olefin sulfonate for the purposes of improving detergency, and discloses examples of application to shampoos, liquid soaps, and the like. Meanwhile, Patent Document 4 describes a promoter for recovering an oil using a surfactant containing a plurality of internal olefin sulfonates differing in the number of carbon atoms.
[Patent Document 1] JP-A-59-222466
[Patent Document 2] JP-A-2003-81935
[Patent Document 3] U.S. Pat. No. 5,078,916
[Patent Document 4] WO-A 2010/129051